Less than four months into Donald Trump's presidency, members of Congress are tossing around the word "impeachment." The British tabloids gush headlines such as, "Will he be impeached?" Bookies there put the odds at 33%.

It's a term — and a process — with a rich and ignominious history.

Two presidents have been impeached, and neither was convicted. A third resigned in disgrace rather than face near-certain conviction. Only eight people have been impeached in the House and convicted in the Senate — all federal judges.

The process is spelled out in the Constitution: Article II, Section 4 specifies that "the President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors."

But what other crimes are impeachable offenses was left for Congress to sort out. President Andrew Johnson was impeached in 1868 for abuse of power, President Bill Clinton 130 years later for perjury and obstruction of justice. Both were acquitted in the Senate.

President Richard Nixon resigned on Aug. 8, 1974, after three articles of impeachment were drafted charging him with obstruction of justice, abuse of power and contempt of Congress. He later was pardoned by his successor, President Gerald Ford.

When he served in the House, Ford famously declared that "an impeachable offense is whatever a majority of the House of Representatives considers it to be at a given moment in history.”

The allegations swirling around President Trump — from contacts with Russian officials during the presidential campaign and sharing classified information with them once in office, to asking FBI Director James Comey to drop charges against former national security adviser Michael Flynn — could provide the seeds for formal charges in the future.

But Trump has at least one thing going for him that his predecessors did not — the Congress that would have to impeach and convict him is controlled by his Republican Party.

Here's a look at the process, which likely would take many months, if not years, to develop:

• First, articles of impeachment are drafted, most likely by the House Judiciary Committee or from the findings of an independent counsel. Notably in the case of Trump, who still faces unanswered questions about his taxes and business dealings, the misdeeds need not have occurred after his election.

• The full House has "the sole Power of Impeachment," according to the Constitution. Each article of impeachment requires a simple majority vote.

• The Senate has "the sole Power to try all Impeachments," with the chief justice of the United States presiding. A two-thirds vote is needed to convict.

• Punishment is severe — at least removal from office, and possibly "disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States."

Congress also can stop short of impeachment and call for a lesser form of censure or sanction. And the 25th Amendment gives it the power to remove a president who is deemed by the vice president and Cabinet officials to be "unable to discharge the powers and duties of his office."